After thinking about it I don't care either way about the "Any craft fix any item" thing. People will eventually get a repair if you can't do it, just open it up so anybody can help everybody. You complain about losing out on repairs but don't forget you will also potentially get a LOT more people to repair, and if you have all crafts at 40+ there's nothing to complain about in the first place. The issue pretty much becomes nonexistent if you still require the craft job at the correct level.

Crafters are supposed to be about making gear, selling items second-hand does not ruin the economy in any game ever and it would happen with your involvement or not. The systems being added are likely to keep gear circulating by going into the economy with simpler repairs and crafts and being removed through Materia.